Systems and methods for reducing efficiency losses associated with powering vehicle accessories

ABSTRACT

Systems and methods for driving an accessory of a vehicle. The system includes a power take-off (PTO) device, a mechanically driven accessory, a battery, and power conversion circuitry electrically connected to the battery. The system also includes a first electric motor mechanically coupled to the PTO device and a second electric motor mechanically coupled to the mechanically driven accessory. The system further includes an engageable mechanical connector that, when engaged, mechanically couples the PTO device and the mechanically driven accessory. The system performs operations including engaging the engageable mechanical connector when a speed of the PTO device is within a predetermined speed range; disengaging the engageable mechanical connector when the speed of the PTO device is outside the predetermined speed range; and based on disengaging the engageable mechanical connector, providing electric power to the second electric motor to generate and transfer mechanical energy to the mechanically driven accessory.

BACKGROUND

Vehicles often have accessories incorporated into the vehicle oraccessories that may be attached and powered by the vehicle. One commonexample of such an accessory is refrigerant compressor as part of aheating, ventilation, and air conditioning (“HVAC”) system that may beused to cool or heat the interior of the vehicle when the vehicle is inoperation or even when the vehicle is not in operation. In somevehicles, a sleeping compartment (“sleeper”) may be attached to a cabin.The driver may rest or sleep in the sleeper either while the seconddriver operates the truck or when the truck is parked, for example, forthe night, during mandatory rest periods, etc. These rest periods in thesleeper are referred to as “hoteling” in the trucking industry. When adriver is hoteling, accessories such as the refrigerant compressor stillrequire power to maintain a comfortable environment within the cabin andsleeper of the vehicle.

It is with respect to these and other general considerations that theaspects disclosed herein have been made. Also, although relativelyspecific problems may be discussed, it should be understood that theexamples should not be limited to solving the specific problemsidentified in the background or elsewhere in this disclosure.

SUMMARY

The present technology relates to reducing efficiency losses associatedwith powering vehicle accessories. In an aspect, the present technologyrelates to a system for driving an accessory of a vehicle. The systemincludes a power take-off (PTO) device, a mechanically driven accessory,a battery, and power conversion circuitry electrically connected to thebattery. The system also includes a first electric motor mechanicallycoupled to the PTO device and electrically connected to the powerconversion circuitry, and a second electric motor mechanically coupledto the mechanically driven accessory and electrically connected to atleast one of the power conversion circuitry or the battery, wherein thesecond electric motor has a smaller power capacity than the firstelectric motor. The system further includes an engageable mechanicalconnector that, when engaged, mechanically couples the PTO device andthe mechanically driven accessory. In addition, the system includes atleast one processor; and memory storing instructions, that when executedby the at least one processor, cause the system to perform a set ofoperations. The set of operations include engaging the engageablemechanical connector when a speed of the PTO device is within apredetermined speed range; disengaging the engageable mechanicalconnector when the speed of the PTO device is outside the predeterminedspeed range; and based on disengaging the engageable mechanicalconnector, providing electric power, from at least one of the battery orthe power conversion circuitry, to the second electric motor to causethe second electric motor to generate and transfer mechanical energy tothe mechanically driven accessory.

In an example, the operations further include accessing a target speedrange of the mechanically driven accessory, wherein the predeterminedspeed range is based on the target speed range. In another example, theengageable mechanical connector includes a clutch configured to engageand disengage the PTO device to and from at least one of the secondelectric motor or a set of gears coupled to the mechanically drivenaccessory. In a further example, the first electric motor is configuredto generate electric power to recharge the battery. In yet anotherexample, the mechanically driven accessory is a refrigerant compressor.

In another aspect, the present technology relates to a system fordriving an accessory of a vehicle. The system includes a power take-off(PTO) device, a first electric motor, a second electric motor, whereinthe second electric motor has a smaller power capacity than the firstelectric motor, and a clutch coupled to a shaft of the second electricmotor and the PTO device. The clutch is configured to engage, such thatthe shaft of the second electric motor is coupled with the PTO devicewhen a speed of the PTO device is within a predetermined speed range;and disengage, such that the shaft of the second electric motor isdecoupled from the PTO device when a speed of the power take-off isoutside the predetermined speed range.

In an example, the second electric motor is coupled to a mechanicallydriven accessory to mechanically couple the PTO device with themechanically driven accessory when the clutch engages the shaft with thePTO device. In another example, the predetermined speed range of thepower take-off is based on a target speed range for a mechanicallydriven accessory. In a further example, the first electric motor isconfigured to convert mechanical energy, transferred from the PTOdevice, to electric energy to charge a battery of the vehicle. In yetanother example, the system further includes electric power conversioncircuitry configured to transfer at least a portion of the electricenergy produced by the first electric motor to the second electric motorwhen the shaft of the second electric motor is decoupled from the PTOdevice. In still another example, the first electric motor is furtherconfigured to crank an engine of the vehicle.

In another example, the present technology relates to a method forcontrolling mechanical power delivery to a mechanically driven accessoryof a vehicle. The method includes receiving a first speed of a powertake-off (PTO) device at a first time; comparing the first speed of thePTO device to a predetermined speed range; and based on the comparisonof the first speed to the predetermined speed range, engaging amechanical connection between an electric motor and the PTO device,wherein engaging the mechanical connection causes mechanical power to betransferred from the PTO device to a mechanically driven accessory. Themethod further includes receiving a second speed of the PTO device at asecond time; comparing the second speed of the PTO device to thepredetermined speed range; and based on the comparison of the secondspeed to the predetermined speed range: disengaging the mechanicalconnection between the electric motor and the PTO device; and applyingelectric power to the electric motor to generate mechanical power thatis transferred to the mechanically driven accessory.

In an example, the predetermined speed range is based on a target speedrange for driving the mechanically driven accessory. In another example,the second speed is higher than the first speed. In yet another example,the mechanically driven accessory is a refrigerant compressor.

In another aspect, the technology relates to a method for controllingmechanical power delivery to a mechanically driven accessory of avehicle. The method includes receiving, by a first electric motor,mechanical power from a drivetrain of the vehicle; generating, by thefirst electric motor, electric power from the mechanical power; chargingat least one battery of the vehicle with the electric power generatedfrom the first electric motor; providing electric power from the atleast one battery to a second electric motor of the vehicle; generating,by the second electric motor, mechanical power from the electric powerprovided by the at least one battery; and driving an accessory of thevehicle with the mechanical power generated from the second electricmotor.

In an example, a power capacity of the second electric motor is smallerthan a power capacity of the first electric motor. In another example,the accessory is refrigerant compressor for cooling an interior of thevehicle. In yet another example, the method further includes cranking,by the first electric motor, an engine of the vehicle. In still anotherexample, generating the mechanical power by the second electric motorincludes turning a shaft of the second electric motor.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Additionalaspects, features, and/or advantages of examples will be set forth inpart in the description which follows and, in part, will be apparentfrom the description, or may be learned by practice of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive examples are described with reference tothe following figures.

FIG. 1 depicts a side view of a vehicle.

FIG. 2A depicts a schematic of an example system of the presenttechnology utilizing a primary electric motor and a secondary electricmotor.

FIG. 2B depicts a schematic of another example system of the presenttechnology utilizing a primary electric motor and a secondary electricmotor.

FIG. 3A depicts an example representation of a secondary electric motorcoupled to a mechanically driven accessory.

FIG. 3B depicts another example representation of a secondary electricmotor coupled to a mechanically driven accessory.

FIG. 4A depicts a power flow representation according to an example ofthe present technology.

FIG. 4B depicts another power flow representation according to anexample of the present technology.

FIG. 4C depicts another power flow representation according to anexample of the present technology.

FIG. 5 depicts an example method for mechanically powering a vehicleaccessory accordingly to present technology.

FIG. 6 depicts another example method for mechanically powering avehicle accessory accordingly to present technology.

FIG. 7 depicts an example method for controlling mechanical powerdelivery to a mechanically driven accessory of a vehicle

FIG. 8 depicts an example method for controlling battery charge levelsof a vehicle.

DETAILED DESCRIPTION

As discussed above, accessories such as refrigerant compressors may beincorporated into or attached to a vehicle. Powering such accessorieshas traditionally been inefficient. For instance, in some systems, thevehicle engine must be running for the heating/cooling system tooperate. In other systems where an electric motor is provided in thevehicle, the electric motor may be used to power the vehicleaccessories. The size of that electric motor, however, leads either toinefficiencies in providing power to the drivetrain of the vehicle orinefficiencies in powering the vehicle accessories. For example, asmaller electric motor cannot produce enough torque or power to crankthe engine or provide power to the drivetrain. In contrast, a largerelectric motor that is better suited to crank the engine of the vehicleor provide power to the drivetrain has significant spin losses. Forinstance, a large 15 kilowatt (kW) electric motor has spin losses ofapproximately 160 Watts (W) at operating speed. Thus, to run thatelectric motor for 10 hours to power a refrigerant compressor while adriver is hoteling in the sleeper, 1.6 kWh of energy needs to be storedin batteries just to overcome the spin losses from the electric motor.Accordingly, additional batteries are required, which leads toadditional weight of the vehicle. In addition, a vehicle accessory suchas a refrigerant compressor requires substantially less power (e.g., 1-3kW) than provided by the large electric motor, leading to additionalefficiency losses.

The present technology provides for systems and methods that, in part,reduce those efficiency losses. To do so, examples of the presenttechnology introduce a secondary electric motor that has a smaller powercapacity than the primary large electric motor. The smaller secondaryelectric motor may be sized to more efficiently power the vehicleaccessory. For instance, where a refrigerant compressor is the primaryaccessory that is to be powered, the secondary electric motor may have apower capacity between about 1-3 kW to correspond to the powerrequirements of the refrigerant compressor. The secondary motor and/orthe vehicle accessory may be coupled to a power take-off (PTO) device ofthe vehicle that transfers mechanical power from the drivetrain of thevehicle. Thus, the vehicle accessory may then be mechanically drivenfrom the power of the drivetrain in certain conditions or mechanicallydriven by the secondary electric motor from power stored in the batteryin other conditions. Thus, the vehicle accessories may be powered moreefficiently and the energy-storage requirements for the batteries of thevehicle may be reduced.

FIG. 1 depicts a side view of a vehicle 100. In the example depicted,the vehicle 100 is a truck that is part of a tractor-trailercombination, which typically includes the tractor or truck having aso-called fifth wheel by which a box-like, flat-bed, or tankersemi-trailer 160 may be attached for transporting cargo or the like.While the vehicle 100 is depicted as a truck in FIG. 1, it should beappreciated that the present technology is applicable to any type ofvehicle where powering a vehicle accessory is desired.

The example vehicle 100 includes a cabin 120 and an attached sleeper140. The sleeper 140 may be equipped with a dedicated heating andcooling system to keep the driver comfortable in different climates.That dedicated heating and cooling system may include a vehicleaccessory, such as the refrigerant compressor discussed herein. Thevehicle 100 may also include an accessory-powering system 180 accordingto the present technology. The components and operations of exampleaccessory-powering systems are discussed in further detail below.

FIG. 2A depicts a schematic of an example system 200A of the presenttechnology utilizing a primary electric motor 210 and a secondaryelectric motor 218. The system 200A may be an example of anaccessory-powering system 180 as depicted in FIG. 1. The system 200Aincludes an engine 202 that is coupled to a transmission 204. The engine202 may be a combustion engine that provides mechanical power to thetransmission 204, as will be appreciated by those having skill in theart. The transmission 204 is coupled to a PTO device 206. The couplingof the transmission 204 to the PTO device 206 may be accomplisheddirectly or indirectly. In general, as used herein, the term “coupling”or “coupled” means that the two components are directly connectedtogether or indirectly connected through one or more interveningcomponents. The PTO device 206 is a device that allows for themechanical power produced by the engine 202 to be transferred to anotherpiece of equipment. The PTO device 206 effectively provides a couplingpoint for obtaining power from the drivetrain of the vehicle, which maybe accomplished through a connection to the transmission 204 or anotherpoint on the drivetrain of the vehicle. For instance, the PTO device 206may include a shaft, socket, plate, flange, or similar component thatspins based on the speed of the drivetrain or transmission 204.Accordingly, additional devices may be attached to that spinning shaftor socket to transfer the mechanical power to another device. Thosehaving skill in the art will appreciate the different types of PTOdevices 206 that are known and commercially available.

The PTO device 206 may be coupled to a first engageable mechanicalconnector (“EMC”) 208, which is in turn coupled to a first or primaryelectric motor 210. The first EMC 208 may be a clutch or other type ofengageable gear that allows for the primary electric motor 210 to beselectively coupled to the PTO device 206. Accordingly, when the firstEMC 208 is engaged and the engine 202 is running, mechanical power istransferred from the PTO device 206 to the primary electric motor 210.The primary electric motor 210 converts that mechanical power toelectric power. When the first EMC 208 is disengaged or the engine 202is not running, no mechanical power is transferred from the PTO device206 to the primary electric motor 210. In some examples, the first EMC208 may not be included in the system 200A, and the primary electricmotor 210 may be permanently coupled to the PTO device 206.

In some examples, the primary electric motor 210 is a large electricmotor that has a power capacity on the order of 10 kW or more. Otherpower capacities are also possible depending on the needs of the vehicleand uses of the primary electric motor 210. The primary electric motor210 may be used for charging the batteries of the vehicle, such asbattery 214, cranking the engine 202, and/or providing power back to thedrivetrain of the vehicle through the transmission 204, among otherpossible functions. Thus, the primary electric motor 210 may be coupledto the transmission 204 to put power back into the drivetrain. Theprimary electric motor 210 may also be coupled to the engine 202 tocrank the engine 202. In addition, the primary electric motor 210 mayalso be electrically connected to primary power conversion circuitry212, which is in turn coupled to the battery 214.

The power conversion circuitry 212 may include power inversion and/orconversion circuitry to modify the electric power generated by theprimary electric motor 210 when the first EMC 208 is engaged and theengine 202 is running. The primary power conversion circuitry 212 mayinvert direct current (DC) power to alternating current (AC) power orconvert AC power to DC power depending on the type of electric powerdelivered from the primary electric motor 210. The primary powerconversion circuitry 212 may also smooth or condition the electric powerreceived from the primary electric motor 210. The primary powerconversion circuitry 212 may also modify the voltage and/or current ofthe electric power from the primary electric motor 210 based on theinput requirements for charging the battery 214.

Electric power may also be provided from the battery 214 to the primaryelectric motor 210. The electric power may be provided through theprimary power conversion circuitry 212. In such operation, the primarypower conversion circuitry 212 may effectively reverse the conversion ofelectric power that was performed when the electric power was providedfrom the primary electric motor 210 to the battery 214. For example, theprimary power conversion circuitry 212 may invert DC power from thebattery 214 to AC power if the primary electric motor 210 operates on ACpower. The primary power conversion circuitry 212 may also modify thevoltage and/or current of the electric power provided by the battery 214based on the requirements or input specifications of the primaryelectric motor 210. The primary electric motor 210 then converts thereceived electric power to mechanical power that may be used to crankthe engine 202 and/or provide power back to the drivetrain via thetransmission 204. In such examples where the primary electric motor 210is being used to generate mechanical power from electric power providedby the battery 214, the first EMC 208 may be disengaged. The secondarypower conversion circuitry 222 may also include an electricallycontrolled switch, such as one or more transistors, relays, or similardevices. The electrically controlled switch allows for power to beselectively transferred to or from the primary electric motor 210 andthe battery 214.

The PTO device 206 may also be coupled to a second or secondary electricmotor 218 via a second EMC 216. The secondary electric motor 218 mayhave a lower power capacity than the primary electric motor 210. Forexample, the secondary electric motor 218 may have a power capacity ofaround 1-3 kW, whereas the primary electric motor 210 may have a powercapacity of 10-15 kW. In some examples, the secondary electric motor 218has a power capacity of less than about 75%, 50%, 25%, 15%, 10%, or 5%of the power of the power capacity of the primary electric motor 210.

The second EMC 216 may be a clutch or other type of engageable gear thatallows for the secondary electric motor 218 to be selectively coupled tothe PTO device 206. Accordingly, when the second EMC 216 is disengagedor the engine 202 is not running, no mechanical power is transferredfrom the PTO device 206 to the secondary electric motor 218. Incontrast, when the second EMC 216 is engaged and the engine 202 isrunning, mechanical power is transferred from the PTO device 206 to thesecondary electric motor 218. The secondary electric motor 218 may thentransfer that mechanical power to a vehicle accessory, such as amechanically driven accessory 220. The mechanically driven accessory 220may be any accessory that may be operated based on mechanical power,such as refrigerant compressor, liquid or air pumps, pneumatic lift, aircompressor, or other types of mechanically driven accessories. Forinstance, the secondary electric motor 218 may effectively mechanicallycouple the mechanically driven accessory 220 and the PTO device 206 whenthe second EMC 216 is engaged. As an example, the secondary electricmotor 218 may be a dual-shafted electric motor where spinning of a firstshaft of the secondary electric motor 218 causes the second shaft of theelectric motor to spin. An example of such a configuration is depictedin FIG. 3A and discussed further below. The secondary electric motor 218may also be mechanically coupled to additional accessories such that thesecondary electric motor 218 may be used to power those additionalaccessories as well. In some examples, the primary electric motor 210may also be mechanically coupled to the mechanically driven accessory220 to power the mechanically driven accessory 220 if the loadrequirements of the mechanically driven accessory 220 exceeds the powercapacity of the secondary electric motor 218.

The secondary electric motor 218 may also be electrically coupled to thebattery 214. In some examples, when the EMC 216 is engaged and theengine 202 is running, the secondary electric motor 218 may convert atleast a portion of the mechanical power transferred from the PTO device206 into electric power that may be used to charge the battery 214. Asecondary power conversion circuitry 222 may also be located between thesecondary electric motor 218 and the battery 214. The secondary powerconversion circuitry 222 may operate in substantially the same manner asthe primary power conversion circuitry 212. For instance, the secondarypower conversion circuitry 222 may modify voltage, current, AC, and/orDC properties of the electric power that is being provided from thesecondary electric motor 218 to the battery 214 and/or electric powerbeing provided from the battery 214 to the secondary electric motor 218.The secondary power conversion circuitry 222 may also include anelectrically controlled switch, such as one or more transistors, relays,or similar devices. The electrically controlled switch allows for powerto be selectively transferred to or from the secondary electric motor218 and the battery 214. In some examples, secondary power conversioncircuitry 222 may be combined with the primary power conversioncircuitry 212 to have one combined set of circuitry for power conversionand modification of electric power to and from the primary electricmotor 210 and the secondary electric motor 218.

When the engine 202 is not running or the speed of the PTO device 206 isnot suitable for operating the mechanically driven accessory 220, thebattery 214 may provide electric power to the secondary electric motor218. The secondary electric motor 218 then converts that electric powerto the mechanical power to mechanically drive the mechanically drivenaccessory 220. The amount of electric power provided to the secondaryelectric motor 218 may be based on the type of mechanically drivenaccessory 220 that is to be powered. For example, the mechanicallydriven accessory 220 may have a target speed for better performance ofthe mechanically driven accessory 220. The electric power provided fromthe battery 214 may then have characteristics, such as a particularvoltage and/or current, that causes the secondary electric motor 218 toproduce mechanical power at the target speed for the mechanically drivenaccessory 220.

The system 200A may also include a computing device 224 that is poweredfrom the battery 214. The computing device 224 includes at least oneprocessor 226 and memory 228. The memory 228 may comprise non-transitorycomputer storage media that stores instructions that, when executed bythe at least one processor 226, causes the system 200A to perform a setof operations or processes described herein. The computing device 224may be in communication with the power conversion circuitry 212 and thesecondary power conversion circuitry 222 to control the electricallycontrolled switches and power modification components therein. Thus,execution of instructions may cause electric power to be transferred tothe primary electric motor 210 and/or the secondary electric motor 218by closing or opening the electrically controlled switches in the powerconversion circuitry 212 and/or the secondary power conversion circuitry222. For instance, the computing device 224 may send a close signal thatcauses the electrically controlled switches to close and an open signalthat causes the electrically controlled switches to open. The computingdevice 224 may also be in communication with the first EMC 208 and/orthe second EMC 216. Accordingly, execution of instructions may engage ordisengage the first EMC 208 and/or the second EMC 216. For instance, thecomputing device 224 may send an engage signal to the first EMC 208and/or the second EMC 216 that causes the first EMC 208 and/or secondEMC 216 to engage. Similarly, the computing device 224 may send adisengage signal to the first EMC 208 and/or the second EMC 216 thatcauses the first EMC 208 and/or second EMC 216 to disengage. Thecomputing device 224 may also be in communication with the engine 202along with other powertrain and vehicle systems.

The at least one processor 226 is a hardware device or combination ofhardware devices, such as one or more microprocessors, a multi-coreprocessor, and/or or a central processing unit (CPU). Depending on theexact configuration and type of computing device 224, memory 228 may benon-transitory computer storage media that is volatile (such as RAM),non-volatile (such as ROM, flash memory, etc.), or some combination ofthe two. Further, memory 228 may also include storage devices(removable, and/or non-removable) including, but not limited to,solid-state, magnetic disks, optical disks, or tape. The computingdevice 224 may also have input and/or output devices such as atouchscreen, keyboard, mouse, pen, voice input, display, speakers,printer, etc. Communication connections may also be included in thecomputing device 224 that allow for further communication with acontroller area network (CAN), local area network (LAN), wide areanetwork (WAN), point-to-point, etc.

In addition, examples of the present technology may be practiced with orin an electrical circuit comprising discrete electronic elements,packaged or integrated electronic chips containing logic gates, acircuit utilizing a microprocessor, or on a single chip containingelectronic elements or microprocessors that effectively operate as thecomputing device 224. For instance, the processor 224 and the memory 226may be packaged together on a single chip or board. As an example,functionality of the present technology may be practiced via asystem-on-a-chip (SOC) where each or many of the components thecomputing device 224 may be integrated onto a single integrated circuit.Such an SOC device may include one or more processors, graphics units,communications units, system virtualization units and variousapplication functionality all of which are integrated onto the chipsubstrate as a single integrated circuit. When operating via an SOC, thefunctionality described herein may be operated via application-specificlogic integrated with other components of the computing device 224 onthe single integrated circuit (chip). Examples of the present disclosuremay also be practiced using other technologies capable of performinglogical operations such as, for example, AND, OR, and NOT, including butnot limited to mechanical, optical, fluidic, and quantum technologies.

FIG. 2B depicts a schematic of an example system 200B of the presenttechnology utilizing a primary electric motor 210 and a secondaryelectric motor 218. System 200B is substantially similar to the system200A depicted in FIG. 2A with the exception of the coupling mechanismsbetween the PTO device 206, the secondary electric motor 218, and themechanically driven accessory. In system 200B, the PTO device 206 iscoupled to the second EMC 216, which is coupled to a set of gears 230 orgearbox. The set of gears 230 is configured to transfer mechanical powerfrom the PTO device 206 to the mechanically driven accessory and/or thesecondary electric motor 218. Similarly, the set of gears 230 isconfigured to transfer mechanical power from the secondary electricmotor to the mechanically driven accessory 220. The set of gears 230 maybe a set of planetary gears, other gears, a chain drive, a belt andpulley system, or another similar system that allows for mechanicalenergy transfer between more than two devices or objects. An example ofsuch a configuration is depicted in FIG. 3B and discussed further below.

FIG. 3A depicts an example representation of a secondary electric motor302 coupled to a mechanically driven accessory 310 (such as mechanicallydriven accessory 220 in FIG. 2A). Such a coupling may be used in system200A depicted in FIG. 2A and discussed above. The secondary electricmotor 302 has a first shaft 304 and a second shaft 306. The secondaryelectric motor 302 also includes terminals or connectors 308 fortransferring or receiving electric power. In the example depicted, whenmechanical power is received at the first shaft 304, such as from a PTOdevice, the first shaft 304 spins, which also causes the second shaft306 to spin. In some examples, the first shaft 304 and the second shaft306 may be part of the same shaft, such as a through-shaft that passesthrough the secondary electric motor 302. The second shaft 306 iscoupled to the mechanically driven accessory 310 such that themechanical power from the spinning second shaft 306 may be transferredto the mechanically driven accessory.

When mechanical power is applied to the first shaft 304 that causes thefirst shaft 304 to spin, the secondary electric motor 302 may convert atleast a portion of that mechanical power to electric power. The electricpower may be transferred to a battery via connectors 308. The connectors308 may also be used to receive electric power from the battery. Whenelectric power is received from the battery, the secondary electricmotor 302 generates mechanical power that causes at least the secondshaft 306 to spin. The spinning second shaft 306, which is coupled tothe mechanically driven accessory 310, transfers the mechanical power tothe mechanically driven accessory 310. Components in addition to thoseshown in the simplified representation depicted in FIG. 3A may also beincluded.

FIG. 3B depicts another example representation of a secondary electricmotor 302 coupled to a mechanically driven accessory 310 (such asmechanically driven accessory 220 in FIG. 2B). Such a coupling may beused in system 200B depicted in FIG. 2B and discussed above. Thesecondary electric motor 302 has a shaft 312 that is coupled to a set ofgears 314. Another input shaft 316 is also coupled to the set of gears314. The input shaft 316 may be coupled to a PTO device. Themechanically driven accessory 310 is coupled to the set of the gears 314via an output shaft 318. When the input shaft 316 spins, such as whenmechanical power is transferred from the PTO device, the output shaft318 also spins. In some examples, spinning of the input shaft 316 alsocauses the shaft 312 of the secondary electric motor 302. When spinningof the input shaft 316 causes the shaft 312 to spin, the secondaryelectric motor 302 may convert the mechanical power to electric powerand transfer that electric power via the connectors 308.

Electric power may also be provided to the secondary electric motor 302via the connectors 308. When electric power is provided or applied tothe secondary electric motor 302, the secondary electric motor 302converts that electric power to mechanical power that causes the shaft312 to spin. The set of gears 314 transfers the mechanical power of theshaft 312 to the output shaft 318, causing the output shaft 318 to spin.The spinning output shaft 318 then powers the mechanically drivenaccessory 310. Accordingly, the mechanically driven accessory 310 may bedriven from mechanical power from the PTO device or mechanical powergenerated from the secondary electric motor 302. Components in additionto those shown in the simplified representation depicted in FIG. 3B mayalso be included.

FIGS. 4A-4C depict different power flow representations based on theoperating conditions of the vehicle. In examples, the power flowrepresentations of FIGS. 4A-4C represent power flow between and amongelements of systems such as those depicted in FIGS. 2A and 2B. Asdiscussed above, the PTO device 404 generally includes a spinning shaft,socket, plate, flange, or similar connection device. The PTO device 404may spin at different speeds, as measured in rotations per minute (RPM)for example. The speed of the PTO device 404 may be largely based on theengine speed and/or the speed of the vehicle. For instance, when theengine 402 is running at a high speed, the speed of the PTO device 404is also high. As another example, if a vehicle is descending a gradeusing an engine brake or a “Jake” brake, the engine speed alsoincreases, which causes the PTO device 404 to operate at a higher speed.In contrast, if the vehicle is ascending a lengthy grade with thetransmission in a lower gear, the engine may be operating a lower speed(e.g., 1500-2000 rpm) and thus the PTO device 404 operates at a lowerspeed. Some speed ranges of the PTO device 404 are acceptable formechanically powering the accessory, while other speed ranges may beunacceptable. The speed ranges may be based on the type of accessorythat is being operated and the target speed ranges of those accessories.In addition, one or more gears (such as gears 230 in FIG. 2B), or othermeans of transmitting mechanical power, may be present between the PTOdevice 404 and the accessory 414 that either step up or step down thespeed from the PTO device 404 to the accessory 414.

FIG. 4A depicts a power flow representation for an operating conditionof the vehicle where the speed of the PTO device 404 is within a rangethat is acceptable to power the mechanically driven accessory 414. Inthe power flow representation of FIG. 4A, mechanical power istransferred from the engine 402 to the transmission and the PTO device404. The mechanical power may be generated from combustion of fuel bythe engine 402 or through recovered energy, such as when the vehicle isdescending a grade. The mechanical power is then transferred from thePTO device 404 to the primary electric motor 406 and the secondaryelectric motor 412. The secondary electric motor 412 transfers themechanical power to the mechanically driven accessory 414. For example,the secondary electric motor 412 mechanically couples the PTO device 404and the mechanically driven accessory 414. In such an example, a secondEMC (such as EMC 216 discussed above in FIG. 2A) is engaged to allow forthe secondary electric motor 412 to be coupled to the PTO device 404.

The primary electric motor 406 converts the mechanical power to electricpower and transfers the electric power to the power conversion circuitry408. The power conversion circuitry modifies the electric power andtransfers the modified electric power to the battery 410 to charge thebattery 410.

FIG. 4B depicts another power flow representation for an operatingcondition of the vehicle where the speed of the PTO device 404 is withina range that is unacceptable to power the mechanically driven accessory414. For example, the engine 402 speed (and thus the PTO device 404speed) may be too high to safely or properly power the accessory 414. Insuch an operating condition, the secondary electric motor 412 isdecoupled from the PTO device 404, such as by disengaging the second EMCdiscussed above in the example system of FIG. 2A.

In the power flow depicted in FIG. 4B, mechanical power from the engine402 is transferred to the transmission and the PTO device 404. Themechanical power is then transferred from the PTO device 404 to theprimary electric motor 406. The primary electric motor 406 converts themechanical power to electric power and transfers that electric power tothe power conversion circuitry 408. The power conversion circuitry 408modifies the electric power and may transfer a portion of the electricpower to the battery 410 to charge the battery 410.

The power conversion circuitry 408 may also transfer a portion of theelectric power to the secondary electric motor 412. The secondaryelectric motor 412 converts the electric power into mechanical powerthat causes a shaft of the secondary electric motor 412 to spin. Thatmechanical power is transferred to the accessory 414 to power or drivethe accessory 414. The power conversion circuitry 408 may modify theelectric power to have voltage and current characteristics appropriatefor the secondary electric motor 412 and to cause the secondary electricmotor 412 to spin at a speed that is within the target speed range forthe accessory 414.

FIG. 4C depicts another power flow representation for an operatingcondition of the vehicle where engine 402 is not running. Such anoperating condition may occur when a driver of the vehicle is hoteling.In such an example, electric energy is transferred from the battery 410to the power conversion circuitry 408. The power conversion circuitry408 modifies the electric power and provides it to the secondaryelectric motor 412. The secondary electric motor 412 converts theelectric power to mechanical power and transfers that mechanical powerto the accessory 414. The power conversion circuitry 408 may modify theelectric power to have voltage and current characteristics appropriatefor the secondary electric motor 412 and to cause the secondary electricmotor 412 to spin at a speed that is within the target speed range forthe accessory 414. In some examples, if the load required by theaccessory 414 exceeds a threshold that can be provided by the battery410 or the electric energy stored in the battery 410 drops below athreshold, the engine may be started to recharge the battery 410 and/orprovide mechanical power to the accessory 414, such as depicted in thepower flow in FIG. 4A.

FIGS. 5-7 depict example methods according to the present technologyherein. The example methods include operations that may be implementedor performed by the systems and devices disclosed herein. For example,the system 200A depicted in FIG. 2A and/or system 200B depicted in FIG.2B may perform the operations described in the methods. For example, thecomputing device 224 in system 200A and system 200B may perform theoperations disclosed herein. In addition, instructions for performingthe operations of the methods disclosed herein may be stored in thememory 228 of computing device 224.

FIG. 5 depicts an example method 500 for controlling mechanical powerdelivery to a mechanically driven accessory of a vehicle according tothe present technology. The method 500 may be executed when a request topower a vehicle accessory is received, such as by a selection from auser. The request to power the vehicle accessory may also be from anautomatic switch, such as a switch that triggers based on temperature inthe cabin and/or sleeper. At operation 502, a speed of a PTO device isreceived or accessed. The speed of the PTO device may be measured fromthe variety of sensors capable of measuring rotation speed, such astachometers, as will be appreciated by those having skill in the art. Insome examples, the speed of the PTO device may also be derived orcalculated from the transmission speed or engine speed, which may bemeasured by a tachometer of the vehicle. Such sensors may be incommunication with a computing device, such as computing device 224depicted in FIGS. 2A-2B, to allow for the computing device to access orreceive the speeds measured by the sensors.

At operation 504, a speed range is accessed. The speed range may be atarget range for the particular vehicle accessory that is to bemechanically powered. For example, the target range may be a range ofrotation speeds that are acceptable to power the accessory. As anexample, when a vehicle accessory is connected to the vehicle, thevehicle accessory may be automatically identified, and a target speedfor the identified accessory may be accessed. Target speeds for multipledifferent accessories may be stored in memory of the computing deviceand accessed as needed. In other examples, target speeds for anidentified accessory may be accessed from a remote source, such as viathe Internet. In some examples, the type of accessory may be manuallyselected or entered by a user. The target speed for the selectedaccessory may then be accessed. Further, the speed range may be enteredmanually by a user. That manually entered speed range may then beaccessed. Thus, the speed range may be preset or predetermined beforethe vehicle accessory is powered by the vehicle.

At operation 506, a comparison is made between the speed of the PTOdevice received in operation 502 and the speed range accessed inoperation 506. If the received speed of the PTO device is within theaccessed speed range, the PTO speed is appropriate to mechanically powerthe vehicle accessory, and method 500 flows to operation 508. Atoperation 508, an EMC between the PTO device and the secondary electricmotor is engaged (or remains engaged) such that mechanical energy istransferred to the accessory. Engaging the EMC may include generating,by a computing device, an engage signal that is transmitted to the EMC,which causes the EMC to engage. Engaging the EMC causes mechanical powerto be transferred to a set of gears and/or to a secondary electric motorthat mechanically couples the accessory and the PTO device. The method500 then flows back to operation 502 where the method repeats.Accordingly, the speed of the PTO device may be continuously orperiodically measured or received and compared to the speed range forthe accessory to determine whether the current speed of the PTO deviceis acceptable for mechanically powering the vehicle accessory.

If, at operation 506, the received speed of the PTO device is outside ofthe accessed speed range, the speed of the PTO device is unacceptablefor mechanically powering the vehicle accessory and method 500 flows tooperation 510 where the EMC between the PTO device and the accessory isdisengaged (or remains disengaged if previously disengaged). Disengagingthe EMC may include generating, by a computing device, a disengagesignal that is transmitted to the EMC, which causes the EMC todisengage. Disengaging the EMC decouples the PTO device from theaccessory.

With the EMC disengaged, electric power is then provided or applied tothe secondary electric motor at operation 512. The secondary electricmotor uses that electric power to generate mechanical power that drivesor powers the accessory. The electric power may be provided to thesecondary electric motor from a battery, similar to the power flowrepresentation shown in FIG. 4C. Providing the electric power from thebattery may occur when the PTO speed is below the accessed speed range,such as when the engine is not running. The electric power may also, oralternatively, be provided to the secondary electric motor from electricpower generated by the primary electric motor, similar to the power flowrepresentation shown in FIG. 4B. For example, the electric power may beprovided from the primary electric motor via the power conversioncircuitry when the speed of the PTO device is higher than the accessedspeed range. Applying or providing electrical power may includegenerating, by a computing device, a signal to close an electricallycontrolled switch between the source of the electric power and thesecondary electric motor. The method 500 then flows back to operation502 where the method 500 repeats.

FIG. 6 depicts another example method 600 for controlling mechanicalpower delivery to a mechanically driven accessory of a vehicle accordingto an example of the present technology. At operation 602, a first speedof a PTO device is received or accessed. The first speed of the PTOdevice corresponds to the speed of the PTO device at first point intime. At operation 604, the first speed of the PTO device is compared toa speed range. The speed range may be any of the speed ranges discussedherein. At operation 606, based on the comparison of the first speed ofthe PTO device and the speed range, a mechanical connection is engagedbetween either the PTO device and the secondary electric motor or thePTO device and a set of gears. Either the secondary electric motor orthe set of gears mechanically couples the PTO device and the vehicleaccessory when the mechanical connection is engaged.

At operation 608, a second speed of the PTO device is received oraccessed. The second speed of the PTO device corresponds to the speed ofthe PTO device at a second point in time. At operation 610, the secondspeed of the PTO device is compared to the speed range. Based on thecomparison of the second speed of the PTO device and the speed range,the mechanical connection between the PTO device and the accessory isdisengaged in operation 612. Operation 612 may also include applyingelectric power to the secondary electric motor, which generatesmechanical power to drive or power the accessory. In an example, thesecond speed of the PTO device is higher than the first speed of the PTOdevice, thus causing the second speed to be above the speed range.

FIG. 7 depicts another example method 700 for controlling mechanicalpower delivery to a mechanically driven accessory of a vehicle accordingto an example of the present technology. At operation 702, mechanicalpower from a drivetrain of a vehicle is received by a first electricmotor. The first electric motor may be the primary electric motordiscussed above. The mechanical power may be transferred from a PTOdevice. At operation 704, the first electric motor generates electricpower from the received mechanical power. For example, the mechanicalpower may be received by the first electric motor in the form ofspinning the shaft of the first electric motor. Spinning of the shaft ofthe first electric motor causes the first electric motor to generateelectric power. The electric power generated by the first electric motoris then used to charge a battery of the vehicle in operation 706.

At operation 708, electric power is provided from the battery to asecond electric motor of the vehicle. The second electric motor may bethe secondary electric motor described herein and may have a powercapacity less than that of the first electric motor. The electric powermay be provided based on detection or determination that a speed of aPTO device is outside a speed range of a vehicle accessory. For example,a computing device may monitor the speed of the PTO device and comparethe speed of the PTO device to a speed range for the accessory. If thespeed of the PTO device is outside the range for the accessory, thecomputing device may cause the electric power to be provided inoperation 708. At operation 710, the second electric motor thengenerates mechanical power from the electric power received from thebattery. The generation of mechanical power may include turning orspinning a shaft of the second electric motor. At operation 712, theaccessory of the vehicle is driven or powered with the mechanical powergenerated from the second electric motor.

In some examples, method 700 may also include providing electric powerfrom the battery to the first electric motor. The first electric motorconverts the received electric power into mechanical energy that may beused to crank the engine of the vehicle or provide power back to thedrivetrain of the vehicle. In additional examples, the first electricmotor may also convert the received electric power into mechanicalenergy that may be used to power the mechanically driven accessory.

FIG. 8 depicts an example method 800 for controlling battery chargelevels of a vehicle. At operation 802, an EMC between the PTO device andthe first electric motor of a vehicle may be engaged. Engagement of theEMC causes mechanical power to be transferred from the PTO device to thefirst electric motor. Engaging the EMC may include generating, by acomputing device, an engage signal that is transmitted to the EMC, whichcauses the EMC to engage. At operation 804, the first electric motorgenerates electric power from the mechanical energy transferred from thePTO device. At operation 806, a battery of the vehicle is charged withthe electric power generated from the first electric motor in operation804.

At operation 808, a determination is made as to whether the battery isfully charged. Determining whether a battery is fully charged may beperformed by measuring the voltage level of the battery. If the voltagelevel of the battery is at the rated or maximum voltage level for thebattery, then the battery is fully charged. Accordingly, thedetermination operation may include measuring a voltage level of thebattery and comparing the measured voltage level to a reference ormaximum voltage level for the battery.

If a determination is made in operation 808 that the battery is notfully charged, the method 800 flows back to operation 802 where the EMCremains engaged and electric power continues to be generated to furthercharge the battery. If, however, a determination is made in operation808 that the battery is fully charged, the method 800 flow to operation810 where the EMC between the PTO device and the first electric motor isdisengaged. Disengaging the EMC may include generating, by a computingdevice, a disengage signal that is transmitted to the EMC, which causesthe EMC to disengage. By disengaging the EMC, the transfer of mechanicalpower from the PTO device to the first electric motor is ceased. Thus,no additional electric power is generated and the battery is not furthercharged even though the engine of the vehicle may still be running.Therefore, overcharging of the battery and the negative outcomesassociated therewith may be substantially prevented.

The embodiments described herein may be employed using software,hardware, or a combination of software and hardware to implement andperform the systems and methods disclosed herein. Although specificdevices have been recited throughout the disclosure as performingspecific functions, one of skill in the art will appreciate that thesedevices are provided for illustrative purposes, and other devices may beemployed to perform the functionality disclosed herein without departingfrom the scope of the disclosure. In addition, some aspects of thepresent disclosure are described above with reference to block diagramsand/or operational illustrations of systems and methods according toaspects of this disclosure. The functions, operations, and/or acts notedin the blocks may occur out of the order that is shown in any respectiveflowchart. For example, two blocks shown in succession may in fact beexecuted or performed substantially concurrently or in reverse order,depending on the functionality and implementation involved.

This disclosure describes some embodiments of the present technologywith reference to the accompanying drawings, in which only some of thepossible embodiments were shown. Other aspects may, however, be embodiedin many different forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments were provided sothat this disclosure was thorough and complete and fully conveyed thescope of the possible embodiments to those skilled in the art.

Further, as used herein and in the claims, the phrase “at least one ofelement A, element B, or element C” is intended to convey any of:element A, element B, element C, elements A and B, elements A and C,elements B and C, and elements A, B, and C. In addition, one havingskill in the art will understand the degree to which terms such as“about” or “substantially” convey in light of the measurementstechniques utilized herein. To the extent such terms may not be clearlydefined or understood by one having skill in the art, the term “about”shall mean plus or minus ten percent.

Although specific embodiments are described herein, the scope of thetechnology is not limited to those specific embodiments. One skilled inthe art will recognize other embodiments or improvements that are withinthe scope and spirit of the present technology. In addition, one havingskill in the art will recognize that the various examples andembodiments described herein may be combined with one another.Therefore, the specific structure, acts, or media are disclosed only asillustrative embodiments. The scope of the technology is defined by thefollowing claims and any equivalents therein.

What is claimed is:
 1. A system for driving an accessory of a vehicle,the system comprising: a power take-off (PTO) device; a mechanicallydriven accessory; a battery; power conversion circuitry electricallyconnected to the battery; a first electric motor mechanically coupled tothe PTO device and electrically connected to the power conversioncircuitry; a second electric motor mechanically coupled to themechanically driven accessory and electrically connected to at least oneof the power conversion circuitry or the battery, wherein the secondelectric motor has a smaller power capacity than the first electricmotor; an engageable mechanical connector that, when engaged,mechanically couples the PTO device and the mechanically drivenaccessory; at least one processor; and memory storing instructions, thatwhen executed by the at least one processor, cause the system to performa set of operations comprising: engaging the engageable mechanicalconnector when a speed of the PTO device is within a predetermined speedrange; disengaging the engageable mechanical connector when the speed ofthe PTO device is outside the predetermined speed range; and based ondisengaging the engageable mechanical connector, providing electricpower, from at least one of the battery or the power conversioncircuitry, to the second electric motor to cause the second electricmotor to generate and transfer mechanical energy to the mechanicallydriven accessory.
 2. The system of claim 1, wherein the operationsfurther comprise accessing a target speed range of the mechanicallydriven accessory, wherein the predetermined speed range is based on thetarget speed range.
 3. The system of claim 1, wherein the engageablemechanical connector includes a clutch configured to engage anddisengage the PTO device to and from at least one of the second electricmotor or a set of gears coupled to the mechanically driven accessory. 4.The system of claim 1, wherein the first electric motor is configured togenerate electric power to recharge the battery.
 5. The system of claim1, wherein the mechanically driven accessory is a refrigerantcompressor.
 6. A system for driving an accessory of a vehicle, thesystem comprising: a power take-off (PTO) device; a first electricmotor; a second electric motor, wherein the second electric motor has asmaller power capacity than the first electric motor; and a clutchcoupled to a shaft of the second electric motor and the PTO device,wherein the clutch is configured to: engage, such that the shaft of thesecond electric motor is coupled with the PTO device when a speed of thePTO device is within a predetermined speed range; and disengage, suchthat the shaft of the second electric motor is decoupled from the PTOdevice when a speed of the power take-off is outside the predeterminedspeed range.
 7. The system of claim 6, wherein the second electric motoris coupled to a mechanically driven accessory to mechanically couple thePTO device with the mechanically driven accessory when the clutchengages the shaft with the PTO device.
 8. The system of claim 6, whereinthe predetermined speed range of the power take-off is based on a targetspeed range for a mechanically driven accessory.
 9. The system of claim6, wherein the first electric motor is configured to convert mechanicalenergy, transferred from the PTO device, to electric energy to charge abattery of the vehicle.
 10. The system of claim 9, further comprisingelectric power conversion circuitry configured to transfer at least aportion of the electric energy produced by the first electric motor tothe second electric motor when the shaft of the second electric motor isdecoupled from the PTO device.
 11. The system of claim 9, wherein thefirst electric motor is further configured to crank an engine of thevehicle.
 12. A method for controlling mechanical power delivery to amechanically driven accessory of a vehicle, the method comprising:receiving a first speed of a power take-off (PTO) device at a firsttime; comparing the first speed of the PTO device to a predeterminedspeed range; based on the comparison of the first speed to thepredetermined speed range, engaging a mechanical connection between anelectric motor and the PTO device, wherein engaging the mechanicalconnection causes mechanical power to be transferred from the PTO deviceto a mechanically driven accessory; receiving a second speed of the PTOdevice at a second time; comparing the second speed of the PTO device tothe predetermined speed range; based on the comparison of the secondspeed to the predetermined speed range: disengaging the mechanicalconnection between the electric motor and the PTO device; and applyingelectric power to the electric motor to generate mechanical power thatis transferred to the mechanically driven accessory.
 13. The method ofclaim 12, wherein the predetermined speed range is based on a targetspeed range for driving the mechanically driven accessory.
 14. Themethod of claim 12, wherein the second speed is higher than the firstspeed.
 15. The method of claim 12, wherein the mechanically drivenaccessory is a refrigerant compressor.
 16. A method for controllingmechanical power delivery to a mechanically driven accessory of avehicle, the method comprising: receiving, by a first electric motor,mechanical power from a drivetrain of the vehicle; generating, by thefirst electric motor, electric power from the mechanical power; chargingat least one battery of the vehicle with the electric power generatedfrom the first electric motor; providing electric power from the atleast one battery to a second electric motor of the vehicle; generating,by the second electric motor, mechanical power from the electric powerprovided by the at least one battery; and driving an accessory of thevehicle with the mechanical power generated from the second electricmotor.
 17. The method of claim 16, wherein a power capacity of thesecond electric motor is smaller than a power capacity of the firstelectric motor.
 18. The method of claim 16, wherein the accessory isrefrigerant compressor for cooling an interior of the vehicle.
 19. Themethod of claim 16, further comprising cranking, by the first electricmotor, an engine of the vehicle.
 20. The method of claim 16, whereingenerating the mechanical power by the second electric motor includesturning a shaft of the second electric motor.